Methods of selective atomic layer deposition

ABSTRACT

Methods of depositing a film selectively onto a first substrate surface relative to a second substrate surface are described. The methods include exposing the substrate surfaces to a blocking compound to selectively form a blocking layer on at least a portion of the first surface over the second surface. The substrate is sequentially exposed to a metal precursor with a kinetic diameter in excess of 21 angstroms and a reactant to selectively form a metal-containing layer on the second surface over the blocking layer or the first surface. The relatively larger metal precursors of some embodiments allow for the use of blocking layers with gaps or voids without the loss of selectivity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 16/382,643, filed Apr. 12, 2019, which claims priority to U.S.Provisional Application No. 62/801,043, filed Feb. 4, 2019, and U.S.Provisional Application No. 62/657,687, filed Apr. 13, 2018, the entiredisclosure of which is hereby incorporated by reference herein.

FIELD

Embodiments of the disclosure generally relate to methods of enhancingselective deposition of a film. More particularly, some embodiments ofthe disclosure are directed to methods of enhancing selective atomiclayer deposition of a film using larger diameter precursors. Moreparticularly, some embodiments of the disclosure are directed to methodsof enhancing selective atomic layer deposition of a metal oxide filmusing alcohols as oxidative reagents.

BACKGROUND

The semiconductor industry faces many challenges in the pursuit ofdevice miniaturization including the rapid scaling of nanoscalefeatures. Such challenges include the fabrication of complex devices,often using multiple lithography steps and etch processes. Furthermore,the semiconductor industry needs low cost alternatives to high cost EUVfor patterning complex architectures. To maintain the cadence of deviceminiaturization and keep chip manufacturing costs down, selectivedeposition has shown promise. It has the potential to remove costlylithographic steps by simplifying integration schemes.

Selective deposition of materials can be accomplished in a variety ofways. For instance, some processes may have inherent selectivity tosurfaces based on their surface chemistry. These processes are rare, andtypically specific to the reactants used, materials formed and thesubstrate surfaces.

Accordingly, almost all precedents to date on selective deposition havebeen focused on developing a better SAM (self-assembled monolayer) forenabling a high level of selectivity. Many processes for selectivedeposition involve rigorous activity in optimizing the SAM formationprocess to attain a certain extent of selectivity. It is believed thatselectivity of a process depends entirely on crystallinity of the SAM.The process of achieving crystalline SAMs is lengthy and, in some cases,can take hours to achieve thereby limiting the effective throughput ofthe process.

The central challenge in achieving high quality selective deposition isminimizing defects (e.g., pin holes) in the SAM layer which are prone todeposition causing unwanted device defects. These pinholes are theprimary cause of selectivity failure. A higher quality SAM layer canminimize pinholes thereby reducing defects, however, this process cantake hours limiting the feasibility of the SAM based process.

Therefore, there is a need in the art for methods of selectivedeposition which do not require a defect free SAM.

Hafnium oxide (HfOx) is commonly used as high k material in nanofabrication. The selective deposition of HfOx on metal materials but noton dielectric materials (e.g. silicon oxide) reduces the number ofprocessing steps in smaller technology nodes.

Current methods of selectively depositing HfOx utilize TEMA-Hf(tetrakis(ethylmethylamino)hafnium) as a metal precursor and water asthe oxidant. Using a SAM, these methods can achieve selectivity up toabout 50-60 Å before the SAM degrades and selectivity is lost.

Therefore, there is a need in the art for methods to selectively depositfilms which do not require a defect free SAM. Additionally, there is aneed in the art for methods to increase selectivity of SAM-based metaloxide deposition processes.

SUMMARY

One or more embodiments of the disclosure are directed to a method ofselective deposition. The methods comprise providing a substrate with afirst surface and a second surface. The substrate is exposed to ablocking compound to selectively form a blocking layer on at least aportion of the first surface over the second surface. The substrate issequentially exposed to a metal precursor and a reactant to selectivelyform a metal-containing layer on the second surface over the blockinglayer or the first surface. The metal precursor has a kinetic diameterof greater than or equal to about 21 angstrom.

Further embodiments of the disclosure are directed to methods ofselective deposition. The methods comprise providing a substrate with afirst material surface and a second material surface. The first materialcomprises SiO₂. The second material comprises copper. The substrate isexposed to n-octadecyltris(dimethylamino)silane to selectively form ablocking layer on at least a portion of the first material surface overthe second material surface. The substrate is sequentially exposed totri-tertbutyl aluminum and water to selectively form an aluminum oxidelayer on the second material surface over the blocking layer or thefirst material surface.

Further embodiments of the disclosure are directed to methods ofselective deposition. The methods comprise providing a substrate with afirst material surface and a second material surface. The first materialcomprises SiO₂. The second material comprises copper. The substrate isexposed to n-octadecyltris(dimethylamino)silane to selectively form ablocking layer on at least a portion of the first material surface overthe second material surface. The substrate is sequentially exposed totetrakis(dimethylamido) titanium and ammonia to selectively form antitanium nitride layer on the second material surface over the blockinglayer or the first material surface.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 illustrates a processing method in accordance with one or moreembodiment of the disclosure; and

FIG. 2 illustrates a processing method in accordance with one or moreembodiment of the disclosure.

DETAILED DESCRIPTION

As used in this specification and the appended claims, the term“substrate” and “wafer” are used interchangeably, both referring to asurface, or portion of a surface, upon which a process acts. It willalso be understood by those skilled in the art that reference to asubstrate can also refer to only a portion of the substrate, unless thecontext clearly indicates otherwise. Additionally, reference todepositing on a substrate can mean both a bare substrate and a substratewith one or more films or features deposited or formed thereon.

A “substrate” as used herein, refers to any substrate or materialsurface formed on a substrate upon which film processing is performedduring a fabrication process. For example, a substrate surface on whichprocessing can be performed include materials such as silicon, siliconoxide, strained silicon, silicon on insulator (SOI), carbon dopedsilicon oxides, silicon nitride, doped silicon, germanium, galliumarsenide, glass, sapphire, and any other materials such as metals, metalnitrides, metal alloys, and other conductive materials, depending on theapplication. Substrates include, without limitation, semiconductorwafers. Substrates may be exposed to a pretreatment process to polish,etch, reduce, oxidize, hydroxylate (or otherwise generate or grafttarget chemical moieties to impart chemical functionality), annealand/or bake the substrate surface. In addition to film processingdirectly on the surface of the substrate itself, in the presentdisclosure, any of the film processing steps disclosed may also beperformed on an underlayer formed on the substrate as disclosed in moredetail below, and the term “substrate surface” is intended to includesuch underlayer as the context indicates. Thus for example, where afilm/layer or partial film/layer has been deposited onto a substratesurface, the exposed surface of the newly deposited film/layer becomesthe substrate surface. What a given substrate surface comprises willdepend on what films are to be deposited, as well as the particularchemistry used.

As used herein, a “patterned substrate” refers to a substrate with aplurality of different material surfaces. In some embodiments, apatterned substrate comprises a first surface and a second surface. Insome embodiments, the first surface comprises a dielectric material andthe second surface comprises a conductive material. In some embodiments,the first surface comprises a conductive material and the second surfacecomprises a dielectric material. In one or more embodiments, the firstsurface may comprise a metal, metal oxide, or H-terminatedSi_(x)Ge_(1−x), and the second surface may comprise a Si-containingdielectric, or vice versa. In some embodiments, a substrate surface maycomprise certain functionality (e.g., —OH, —NH, etc.).

As used in this specification and the appended claims, the terms“reactive gas”, “precursor”, “reactant”, and the like, are usedinterchangeably to mean a gas that includes a species which is reactivewith a substrate surface. For example, a first “reactive gas” may simplyadsorb onto the surface of a substrate and be available for furtherchemical reaction with a second reactive gas.

In recent decades, the semiconductor community has made attempts toimprove integrated circuit (IC) processing by replacing lithographysteps with alternatives that translate to lower cost, reduced processingtime, and smaller feature sizes. Many of these alternatives fall underthe blanket category of “selective deposition.” In general, selectivedeposition refers to a process for which the net deposition rate ishigher on the target substrate material relative to other substratematerials, such that the desired film thickness is achieved on thetarget substrate material with less or negligible deposition on theother substrate materials (where “negligible” is defined by processconstraints).

Embodiments of the disclosure provide methods of selectively depositinga film onto one surface over a second surface. As used in thisspecification and the appended claims, the term “selectively depositinga film on one surface over another surface”, and the like, means that afirst amount of the film is deposited on the first surface and a secondamount of film is deposited on the second surface, where the secondamount of film is less than the first amount of film, or no film isdeposited on the second surface. The term “over” used in this regarddoes not imply a physical orientation of one surface on top of anothersurface, rather a relationship of the thermodynamic or properties of thechemical reaction with one surface relative to the other surface. Forexample, selectively depositing a cobalt film onto a copper surface overa dielectric surface means that the cobalt film deposits on the coppersurface and less or no cobalt film deposits on the dielectric surface;or that the formation of the cobalt film on the copper surface isthermodynamically or kinetically favorable relative to the formation ofa cobalt film on the dielectric surface.

One strategy to achieve selective deposition employs the use of blockinglayers in which a blocking layer is formed on substrate materials uponwhich deposition is to be avoided with negligible impact to the targetsubstrate material. A film can be deposited on the target substratematerial while deposition on other substrate materials is “blocked” bythe blocking layer. The blocking layer can be optionally removed withoutnet adverse effects to the deposited film.

Some embodiments of the disclosure incorporate a blocking layertypically referred to as a self-assembled monolayer (SAM) or SAM layer.A self-assembled monolayer (SAM) consists of an ordered arrangement ofspontaneously assembled organic molecules (SAM molecules) adsorbed on asurface. These molecules are typically comprised of one or more moietieswith an affinity for the substrate (head group) and a relatively long,inert, linear hydrocarbon moiety (tail group). Fundamentally, SAMmolecules are surfactants which have a hydrophilic functional head witha hydrophobic carbon chain tail.

In this case, SAM formation happens through fast adsorption of molecularhead groups at the surface and slow association of molecular tail groupswith each other through van der Waals interactions. SAM precursors arechosen such that the head group selectively reacts with the substratematerials to be blocked during deposition. Deposition is then performed,and the SAMs can be removed through thermal decomposition (withdesorption of any byproducts) or an integration-compatible ashingprocess.

Fundamentally the SAM growth on a surface is a chemisorption process.Determined by chemisorption kinetics, the coverage of a SAM layerfollows the Elovich equation

$\frac{d_{q}}{d_{t}} = {\alpha\mspace{14mu}\exp\mspace{14mu}\left( {{- \beta}\; q} \right)}$where q is the amount of chemisorption, t is time, α is the initial rateof chemisorpotion (mmol/g-min) and β is the desorption constant(g/mmol). Accordingly the coverage of a blocking layer as the functionof time follows an asymptotic trend. As a result, the selectivity of ALDdepositions typically follows a similar trend as well (i.e. as coverageincreases, selectivity also increases).

As a general rule, the selectivity of SAM-based deposition processesdepends on the coverage of the SAM blocking layer. Yet there are severalfactors which may impact the selectivity of a given process. Typical ALDprocesses utilize small metal precursors which are more likely to beeasily volatilized into the reaction chamber. Without being bound bytheory, unless coverage is nearly complete, these small metal precursorsare able to adsorb to the substrate surface through gaps or defects inthe blocking layer leading to deposition on the protected surface,thereby reducing selectivity and increasing the likelihood of devicefailure. In order to maximize selectivity, typical selective depositiontechniques require extended exposure times (measured in hours and days).These extended processing times decrease device throughput.

Additionally, the coverage of the SAM may be affected by exposure to thedeposition reactants or certain process conditions during deposition aswell. For example, a SAM layer may become degraded by exposure to harshoxidants. Without being bound by theory, these oxidants may react withthe hydrophobic carbon tail groups to form reactive —OH terminations. Asthese terminations increase in density on the SAM, it may be possiblefor certain reactions which were previously thermodynamicallyunfavorable on the SAM surface to become more favorable. This shift indynamics can lead to nucleation or deposition on the SAM and results ina loss of selectivity. Notably, this loss in selectivity may occurwithout any change in coverage.

Some embodiments of the disclosure provide methods of selectivedeposition which advantageously provide similar selectivity with lowerlevels of coverage and require shorter SAM exposure times through theuse of larger metal precursors which are less able to adsorb to thesubstrate surface through gaps or defects in the blocking layer.

Referring to FIG. 1 , one or more embodiment of the disclosure isdirected to a processing method 100. A substrate 105 is provided with afirst material 110 and a second material 120. The first material 110 hasa first surface 112 and the second material 120 has a second surface122. The first surface and the second surface may also be referred to asthe first material surface and the second material surface.

In some embodiments, the first material 110 comprises a metal oxide or adielectric material and the second material comprises a metal orsilicon. In some embodiments, the first material comprises or consistsessentially of silicon dioxide (SiO₂).

In some embodiments, the second material comprises a metal oxide or adielectric material and the first material comprises a metal or silicon.In some embodiments, the second material comprises or consistsessentially of silicon dioxide (SiO₂).

In some embodiments, the first material 110 comprises a dielectricmaterial and the second material 120 comprises a conductive material. Insome embodiments, the first material 110 comprises a conductive materialand the second material 120 comprises a dielectric material. In someembodiments, the dielectric material comprises one or more of siliconoxide, silicon nitride or silicon carbide. In some embodiments, theconductive material comprises one or more of ruthenium, copper orcobalt. In some embodiments, the first surface comprises a dielectricmaterial consisting essentially of silicon nitride and the secondsurface conductive material consisting essentially of ruthenium. As usedin this specification and the appended claims, the term “consistsessentially of” means that greater than or equal to about 95%, 98%, 99%or 99.5% of the specified material is the stated material.

The first surface 112 is exposed to a blocking compound to selectivelyform a blocking layer 130 on at least a portion of the first surface 112over the second surface 122. In some embodiments, the blocking layer 130contains defects 131 that expose portions 114 of the first surface 112.

The substrate may be exposed to the blocking compound by any suitableprocess. In some embodiments, the substrate is exposed to the blockingcompound by a chemical vapor deposition (CVD) process. In someembodiments, the substrate is exposed to the blocking compound by an ALDprocess. In some embodiments, the substrate is exposed to the blockingcompound by an immersion or “wet” process.

The blocking compound may be any compound capable of selectively forminga blocking layer on the first surface over the second surface. Theblocking compound comprises at least one blocking molecule. In someembodiments, the blocking molecule has the general formula A-L, where Ais a reactive head group and L is a carbonaceous tail group. In someembodiments, the blocking molecule comprises or consists essentially ofn-octadecyltris(dimethylamino)silane.

As used in this manner, the “head group” is a chemical moiety thatassociates with the first surface 112 and the “tail group” is a chemicalmoiety that extends away from the first surface 112.

In some embodiments, the first material 110 comprises a metal oxide or adielectric material and A is selected from the group consisting of(R₂N)₃Si—, X₃Si— and (RO)₃Si—, where each R is independently selectedfrom C1-C6 alkyl, C1-C6 cycloakyl and C1-C6 aryl, and each X isindependently selected from halogens.

In some embodiments, the first material 110 comprises a metal, silicon,or conductive material and A is selected from the group consisting of(HO)₂OP—, HS— and H₃Si—.

Some of the reactive head groups listed above comprise more than onereactive moiety in a single reactive head group (e.g. H₃Si— may bond upto three times with the surface) which is attached to tail group, L. Insome embodiments, A is selected from reactive groups where less than thenumber of reactive moieties listed above and is attached to more thanone tail group, L. In these embodiments, the tail groups may be the sameor different.

In some embodiments, L is —(CH₂)_(n)CH₃ and n is an integer from 3 to24. In some embodiments, the linking group L comprises less than 18carbon atoms. In some embodiments, the linking group comprises less than17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, or 5 carbon atoms.

In some embodiments, L is —(CH₂)_(n)— and n is an integer from 4 to 18and a reactive group is on the end of the tail group opposite the headgroup. In some embodiments, the tail group may be branched with multipleterminations. In some embodiments, the tail group may be substitutedwith reactive groups in a position other than the end of the tail group.In some embodiments, the tail group may be unsaturated. In someembodiments, the tail group may comprise cycloalkyl or aryl groups.

In some embodiments, the blocking molecule includes a reactive group Z.The reactive group Z of some embodiments is a group comprising one ormore reactive moiety selected from alkenes, alkynes, alcohols,carboxylic acids, aldehydes, acyl halides, amines, amides, cyanates,isocyanates, thiocyanates, isothiocyanates, or nitriles.

In some embodiments, the blocking molecule comprises more than onereactive moiety, Z. In some embodiments, A is linked to more than onetail group each terminated with a reactive group, such that a blockingmolecule comprises more than one reactive moiety, Z. In someembodiments, L is branched, such that a blocking molecule comprises morethan one reactive moiety, Z.

In some embodiments, the blocking molecule comprises more than onereactive moiety and the reactive moieties are positioned in a linearfashion. In some embodiments, L comprises more than one reactive moietyand the reactive moieties are positioned in a branched fashion. As usedin this manner, reactive moieties positioned in a linear fashion arepositioned within a blocking molecule such than they are positionedwithin the same carbon chain. In other words, they are positionedend-to-end. As used in this manner, reactive moieties positioned in abranched fashion are positioned within a blocking molecule such thanthey are positioned on different carbon chains. In other words, they arenot positioned end-to-end. In some embodiments, the reactive moietiesmay be separated by intervening atoms but still be consideredend-to-end.

For example, Compound I contains one reactive moiety. Compounds II andIII each contain two reactive moieties. Compound II has reactivemoieties positioned in a linear fashion. Compound III has reactivemoieties positioned in a branched fashion.

In some embodiments, the tail groups associate with each other throughrelatively slow van der Waals interaction. In some embodiments, the tailgroups can be the same or different so that a homogeneous orheterogeneous SAM can be formed. In some embodiments, the blockingcompound comprises at least two different blocking molecules so that aheterogeneous SAM is formed.

The blocking compound can be delivered to the substrate as a singlecompound or sequential exposures of multiple compounds to form ablocking layer 130. In some embodiments, the first surface 112 isexposed to a single compound that assembles on the surface in an orderedor semi-ordered manner.

In some embodiments, the blocking layer 130 contains defects 131. Adefect 131 is a gap or void in the blocking layer where no blockingmolecule has reacted with the first surface 112 to inhibit subsequentdeposition. The defects expose portions 114 of the first surface 112,referred to herein as exposed portions 114 of the first surface 112.

One skilled in the art will understand that after forming the blockinglayer 130, the first surface 112 may have exposed portions 114 as wellas covered portions or blocked portions. In some embodiments, theportion of the first surface covered by the blocking layer is greaterthan or equal to about 80%, or greater than or equal to about 85%, orgreater than or equal to about 90%, or greater than or equal to about95%, or greater than or equal to about 98%, or greater than or equal toabout 99%, or greater than or equal to about 99.5%, or greater than orequal to about 99.9% of the first surface 112 on a cross sectional areabasis.

After formation of the blocking layer 130, a metal-containing layer 115is formed on the second surface 122. In some embodiments, themetal-containing layer is formed by sequentially exposing the substrate105 to a metal precursor and a reactant. The metal-containing layer 115may be deposited by any suitable process. In some embodiments, themetal-containing layer 115 is deposited by CVD. In some embodiments, themetal-containing layer 115 is deposited by ALD. In some embodiments, themetal-containing layer 115 is deposited by exposing the substrate to aplurality of reactants. In some embodiments, the plurality of reactantsis exposed to the substrate sequentially. In some embodiments, theplurality of reactants is exposed to the substrate separately. In someembodiments, the plurality of reactants is separated temporally. In someembodiments, the plurality of reactants is separated spatially.

The amount of the metal-containing layer 115 formed on the first surface112 is less than the amount of the film formed on the second surface122. A measurement of the amount of metal-containing layer 115 formed onthe surfaces can be the average thickness of the metal-containing layerformed on each surface. In some embodiments, the metal-containing layer115 has a first average thickness on the first surface 112 and a secondaverage thickness on the second surface 122. Described differently, theformation of the metal-containing layer 115 may be described asselectively forming a metal-containing layer 115 on the second surface122 over the first surface 112.

The metal precursor can be any suitable precursor with a relativelylarge diameter. In some embodiments, the metal precursor has a kineticdiameter of greater than or equal to about 20.5 angstroms, or greaterthan or equal to about 21.0 angstroms, or greater than or equal to about21.5 angstroms, or greater than or equal to about 22.0 angstroms, orgreater than or equal to about 22.5 angstroms, or greater than or equalto about 23.0 angstroms, or greater than or equal to about 23.5angstroms, or greater than or equal to about 24 angstroms, or greaterthan or equal to about 25 angstroms, or greater than or equal to about26 angstroms, or greater than or equal to about 27 angstroms, or greaterthan or equal to about 28 angstroms.

In some embodiments, the metal precursor comprises a period 3 metal. Insome embodiments, the metal precursor comprises a period 4 metal. Insome embodiments, the metal precursor comprises a period 5 metal. Insome embodiments, the metal precursor comprises a period 6 metal. Asused in this regard, a group X metal is any metal or metalloid from thecorresponding row or period of the periodic table. Accordingly, period 3metals have atomic numbers from 11-14. Period 4 metals have atomicnumbers from 19-33. Period 5 metals have atomic numbers from 37-52.Period 6 metals have atomic numbers from 55-84. Without being bound bytheory, it is believed that metals from higher periods will generallyhave larger kinetic diameters, leading to metal precursors with largerkinetic diameters.

In some embodiments, the metal precursor comprises one or more of Al,Hf, Zr, Y, Ti, Ta, Si, Cu, Co, W, or Ru. In some embodiments, the metalprecursor comprises or consists essentially of tri-tertbutyl aluminum ortri-neopentyl aluminum. In some embodiments, the metal precursorcomprises or consists essentially of tetrakis(dimethylamido)titanium ortetrakis(diethylamido)titanium.

Without being bound by theory, it is believed that these metalprecursors are relatively larger in kinetic diameter than otherprecursors typically used for deposition of these metals. Therefore,despite defects 131 in the blocking layer 130, methods which utilizethese precursors are more selective than smaller, conventionalprecursors like trimethylaluminum or titanium tetrachloride.

One skilled in the art will recognize that a molecular diameter is thedistance between farthest atoms, whereas the kinetic diameter alsoincludes effects of the electron cloud, which can extend substantiallyfarther in space than the atoms, effectively making the molecule larger.

Kinetic diameter can be calculated based on a molecular electronicvolume. The molecular electronic volume is defined as the volume insidea contour of 0.001 electrons/Bohr³ density. Assuming that the volume isspherical, a kinetic diameter can be calculated.

In some embodiments, the metal-containing layer 115 comprises metalatoms and oxygen atoms, nitrogen atoms, carbon atoms, or combinationsthereof. In some embodiments, the metal-containing layer 115 comprises ametal oxide. In some embodiments, the metal-containing layer 115comprises a metal nitride. In some embodiments, metal-containing layer115 comprises a metal carbide. As used in this regard, a metal oxide isany material comprising a metal or silicon atoms and oxygen atoms. Themetal oxide may or may not comprise a stoichiometric ratio of metal tooxygen. Similarly, a metal nitride comprises metal or silicon atoms andnitrogen atoms and a metal carbide comprises metal or silicon atoms andcarbon atoms, both without any predefined atomic ratio.

In some embodiments, the metal-containing layer comprises oxygen atomsand the reactant comprises one or more of water, alcohol, oxygen gas(O₂), ozone or peroxide. In some embodiments, the reactant consistsessentially of water.

In some embodiments, the metal-containing layer comprises nitrogen atomsand the reactant comprises one or more of nitrogen gas (N₂), ammonia,hydrazine, hydrazine derivatives, N₂O or NO₂. In some embodiments, thereactant consists essentially of nitrogen gas or ammonia.

In some embodiments, the metal-containing layer comprises a pure metalfilm. As used in this regard, a “pure” metal film comprises greater than95%, 98%, 99% or 99.5% metal atoms on an atomic basis. In someembodiments, the reactant comprises or consists essentially of hydrogengas (H₂).

Some embodiments of the disclosure provide methods to selectivelydeposit metal oxide materials which advantageously provide increasedselectivity through the use of alcohols as oxidizing reactants which areless likely to degrade the blocking layer.

Referring to FIG. 2 , one or more embodiment of the disclosure isdirected to a processing method 200. A substrate 205 is provided with afirst material 210 and a second material 220. The first material 210 hasa first surface 212 and the second material 220 has a second surface222. The first surface and the second surface may also be referred to asthe first material surface and the second material surface.

In some embodiments, the first material 210 comprises a metal oxide or adielectric material and the second material comprises a metal orsilicon. In some embodiments, the first material comprises or consistsessentially of silicon dioxide (SiO₂).

In some embodiments, the first material 210 comprises a dielectricmaterial and the second material 220 comprises a conductive material. Insome embodiments, the first material 210 comprises a conductive materialand the second material 220 comprises a dielectric material.

In some embodiments, the dielectric material comprises one or more ofsilicon oxide, silicon nitride or silicon carbide. In some embodiments,the conductive material comprises one or more of silicon or a metal. Insome embodiments, the dielectric material consists essentially ofsilicon oxide and the conductive material consists essentially ofsilicon. As used in this specification and the appended claims, the term“consists essentially of” means that greater than or equal to about 95%,98%, 99% or 99.5% of the specified material is the stated material.

The substrate 205 is exposed to a blocking compound to selectively forma blocking layer 230 on at least a portion of the first surface 212 overthe second surface 222. The blocking compound and the blocking layer maybe any suitable blocking compound or blocking layer as describedelsewhere herein.

After formation of the blocking layer 230, a metal oxide layer 215 isformed on the second surface 222. In some embodiments, the metal oxidelayer 215 is formed by sequentially exposing the substrate 205 to ametal precursor and an oxygenating agent. Stated differently, in someembodiments, the metal oxide layer 215 is deposited by ALD. In someembodiments, the metal oxide layer 215 is deposited by exposing thesubstrate to a plurality of reactants. In some embodiments, theplurality of reactants is exposed to the substrate sequentially. In someembodiments, the plurality of reactants is exposed to the substrateseparately. In some embodiments, the plurality of reactants is separatedtemporally. In some embodiments, the plurality of reactants is separatedspatially.

The amount of the metal oxide layer 215 formed on the first surface 112is less than the amount of the layer formed on the second surface 222. Ameasurement of the amount of metal oxide layer 215 formed on thesurfaces can be the average thickness of the metal oxide layer formed oneach surface. In some embodiments, the metal oxide layer 215 has a firstaverage thickness on the first surface 212 and a second averagethickness on the second surface 222. Described differently, theformation of the metal oxide layer 215 may be described as selectivelyforming a metal oxide layer 215 on the second surface 222 over the firstsurface 212.

The metal precursor can be any suitable precursor. In some embodiments,the metal precursor comprises one or more of Al, Hf, Zr, Y, Ti, Ta, Si,Cu, Co, W, or Ru. In some embodiments, the metal precursor compriseshafnium. In some embodiments, the metal precursor comprises or consistsessentially of tris(dimethylamido)cyclopentadienyl hafnium. In someembodiments, the metal precursor comprises or consists essentially oftetrakis(ethylmethylamino)hafnium.

The oxygenating agent can be selected to improve selectivity. Theinventors have found that using oxygenating agents which are relativelylower oxidation potential (i.e. higher pKa values) provides increasedselectivity. In some embodiments, the oxygenating agent has a pKagreater than the pKa of water. In some embodiments, the oxygenatingagent has a pKa greater than or equal to about 14.0 at 25° C. As used inthis specification and the appended claims, the pKa of any statedcompound or species is measured at 25° C. and 1 atm pressure. In someembodiments, the pKa of the oxygenating agent is in the range of about15.8 to about 20, or in the range of about 16 to about 18. In someembodiments, the oxygenating agent has a pKa greater than or equal toabout 15.7. In some embodiments, the oxygenating agent comprisessubstantially no water. In some embodiments, the oxygenating agentcomprises substantially no oxygen (O₂). In some embodiments, theoxygenating agent comprises substantially no ozone (O₃). As used in thismanner, the phrase “substantially no” means that the oxygenating agentcomprises less than or equal to about 5%, 2%, 1% or 0.5% of the statedspecies on a molar basis.

In some embodiments, the oxygenating agent comprises an alcohol. In someembodiments, the oxygenating agent is of the general formula R—OH, whereR is an alkyl or cycloalkyl group comprising 1 to 8 carbons. In someembodiments, R is not an aryl group (e.g., benzyl group).

In some embodiments, the oxygenating agent comprises one or more of:methanol, ethanol, propanol, isopropanol, butanol, sec-butanol ort-butanol. In some embodiments, the oxygenating agent consistsessentially of t-butanol.

In some embodiments, the sequential exposure of the substrate to a metalprecursor and an oxygenating agent is repeated until a predeterminedthickness of metal oxide layer is formed on the first surface. In someembodiments, the sequential exposure of the substrate to a metalprecursor and an oxygenating agent is repeated until substantialdeposition of the metal oxide layer is observed on the blocking layer.As used in this regard, “substantial deposition” refers to thenucleation or other deposition of metal oxide which is observable bySEM.

In some embodiments, the predetermined thickness of metal oxide isformed without substantial deposition on the blocking layer. In someembodiments, the predetermined thickness is greater than or equal toabout 60 Å, greater than or equal to about 80 Å, greater than or equalto about 90 Å, or greater than or equal to about 100 Å.

Without being bound by theory, it is believed that the oxygenatingagents disclosed herein have a lower oxidation potential than water oroxygen. Accordingly, it is believed that these oxygenating agentsminimize metal oxidation, corrosion and particle issues, and are lesscorrosive or otherwise damaging to the SAM layer. Therefore, it ispossible to perform a greater number of deposition cycles and achieve agreater thickness of metal oxide with these oxygenating agents.

The inventors have observed experimentally that deposition of hafniumoxide on a blocked surface occurs after approximately 50 cycles whenformed using a hafnium precursor and water. Yet, when a similar processis performed with t-butanol, no deposition is observed for about 150cycles. Stated differently, when formed with t-butanol, the inventorsare able to deposit about 85-100 Å of hafnium oxide on a silicon surfacewithout substantial deposition on a blocked silicon oxide surface. Yet,when performed with water, the inventors are only able to deposit 30-40Å before deposition is observed on the blocked surface.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe disclosure. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the disclosure.Furthermore, the particular features, structures, materials, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present invention without departing from the spirit andscope of the invention. Thus, it is intended that the present inventioninclude modifications and variations that are within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A selective deposition method comprising:providing a substrate with a first surface comprising a conductivematerial and a second surface comprising a dielectric material; exposingthe substrate to a blocking compound to selectively form a blockinglayer on at least a portion of the first surface over the secondsurface; and sequentially exposing the substrate to a metal precursorcomprising tri-neopentyl aluminum and a reactant to selectively form ametal-containing layer on the second surface over the blocking layer orthe first surface.
 2. The method of claim 1, wherein the blockingcompound comprises a blocking molecule with a reactive head group and acarbonaceous tail group, the reactive head group selected from the groupconsisting of (HO)₂O—, HS—and H₃Si—.
 3. The method of claim 1, whereinthe metal precursor further comprises tri-tertbutyl aluminum.
 4. Themethod of claim 1, wherein the metal-containing layer comprises metalatoms and oxygen atoms, nitrogen atoms, carbon atoms, or combinationsthereof.
 5. The method of claim 4, wherein the metal-containing layercomprises oxygen atoms and the reactant comprises one or more of water,alcohol, oxygen gas (O₂), ozone or peroxide.
 6. The method of claim 4,wherein the metal-containing layer comprises nitrogen atoms and thereactant comprises one or more of nitrogen gas (N₂), ammonia, hydrazine,hydrazine derivatives, N₂O or NO₂.
 7. The method of claim 1, wherein themetal-containing layer comprises a pure metal film.
 8. The method ofclaim 7, wherein the reactant comprises one or more of hydrogen gas(H₂).
 9. The method of claim 1, wherein the portion of the first surfacecovered by the blocking layer is greater than or equal to about 90% ofthe first surface.
 10. A selective deposition method comprising:providing a substrate with a first surface and a second surface;exposing the substrate to a blocking compound to selectively form ablocking layer on at least a portion of the first surface over thesecond surface; and sequentially exposing the substrate to a metalprecursor and a reactant to selectively form a metal-containing layer onthe second surface over the blocking layer or the first surface, themetal precursor comprising tri-neopentyl aluminum.
 11. The method ofclaim 10, wherein the first surface comprises a dielectic material andthe second surface comprises a conductive material.
 12. The method ofclaim 11, wherein the blocking compound comprises a blocking moleculewith a reactive head group and a carbonaceous tail group, the reactivehead group is selected from the group consisting of (R₂N)₃Si—, X₃Si— and(RO)₃Si—, where each R is independently selected from C1-C6 alkyl, C1-C6cycloakyl and C1-C6 aryl, and each X is independently selected fromhalogens.
 13. The method of claim 10, wherein the metal precursorfurther comprises tri-tertbutyl aluminum.
 14. The method of claim 10,wherein the metal-containing layer comprises metal atoms and oxygenatoms, nitrogen atoms, carbon atoms, or combinations thereof.
 15. Themethod of claim 14, wherein the metal-containing layer comprises oxygenatoms and the reactant comprises one or more of water, alcohol, oxygengas (O₂), ozone or peroxide.
 16. The method of claim 14, wherein themetal-containing layer comprises nitrogen atoms and the reactantcomprises one or more of nitrogen gas (N₂), ammonia, hydrazine,hydrazine derivatives, N₂O or NO₂.
 17. The method of claim 10, whereinthe metal-containing layer comprises a pure metal film.
 18. The methodof claim 17, wherein the reactant comprises one or more of hydrogen gas(H₂).
 19. The method of claim 10, wherein the portion of the firstsurface covered by the blocking layer is greater than or equal to about90% of the first surface.
 20. A selective deposition method comprising:providing a substrate with a first material surface and a secondmaterial surface, the first material comprising SiO₂, the secondmaterial comprising copper; exposing the substrate ton-octadecyltris(dimethylamino)silane to selectively form a blockinglayer on at least a portion of the first material surface over thesecond material surface; and sequentially exposing the substrate totri-neopentyl aluminum and water to selectively form an aluminum oxidelayer on the second material surface over the blocking layer and overthe first material surface.